Rational and Combinatorial Design of Peptide Capping Ligands for Gold Nanoparticles

Abstract

Based on protein folding considerations, a pentapeptide ligand, CALNN, which converts citrate-stabilized gold nanoparticles into extremely stable, water-soluble gold nanoparticles with some chemical properties analogous to those of proteins, has been designed. These peptide-capped gold nanoparticles can be freeze-dried and stored as powders that can be subsequently redissolved to yield stable aqueous dispersions. Filtration, size-exclusion chromatography, ion-exchange chromatography, electrophoresis, and centrifugation can be applied to these particles. The effect of 58 different peptide sequences on the electrolyte-induced aggregation of the nanoparticles was studied. The stabilities conferred by these peptide ligands depended on their length, hydrophobicity, and charge and in some cases resulted in further improved stability compared with CALNN, yielding detailed design criteria for peptide capping ligands. A simple strategy for the introduction of recognition groups is proposed and demonstrated with biotin and Strep-tag II.

Structural and optical characterization of pure and starch-capped ZnO quantum dots and their photocatalytic activity

“…It can be carried out at high or low temperature depending on the reactants (Wing et al 2012). Indeed, organic molecules capped with inorganic nanostructures introduce a new type of photophysical and photochemical properties resulting from the combinatorial effects of organic and inorganic phases (Wilkes et al 1985;Levy et al 2004). For instance, conjugated ZnO nanostructure could extend the absorption band up to the visible region and can play an important role in the photocatalytic degradation which could enhance high photocatalytic activity (Qiu et al 2008;Sudha et al 2013).…”

A green chemical approach for the synthesis of gold nanoparticles: characterization and mechanistic aspect

“…For each application, NPs of different size and shape are needed (Jin et al 2001;Sun and Xia 2002), thereby synthetic protocols for the production of size and shape controlled monodisperse NPs are required. Since Faraday's pioneering work in 1857 on the synthesis of colloidal gold by reducing NaAuCl 4 with a solution of phosphorus in carbon disulphide ( citrate or sodium borohydride, followed by surface modification of the produced particles with suitable capping ligands and organic solvents (Niemeyer et al 1998;Lévy et al 2004), raised environmental concerns, because of the toxic compounds used in the process. Also, it is difficult to obtain NPs of defined size and shapes (e.g.…”

Controlled assembly of peptide-functionalized gold nanoparticles for label-free detection of blood coagulation Factor XIII activity

“…2a, red), which is in agreement with previous results on CALNN-functionalized AuNPs. 33 Under the same physiological conditions, non-functionalized AuNPs aggregated instantly due to the charge screening effect and exhibited an absorbance peak at longer wavelength (Fig. 2a, black).…”

“…The rationale behind the design of these peptides is as follows: (i) conjugation of pentapeptide CALNN to the surface of AuNPs promotes stability of the particles at physiological salt concentration; 33 (ii) cysteine (C) residue facilitates the immobilization of the peptides to AuNP surfaces via thiol-gold chemistry; and (iii) glutamine (Q) and lysine (K) residues act as substrates for Factor XIII.…”

“…This is likely due to the strong interaction of amino groups of lysine residues with Au surfaces 34 that may alter the configuration of CALNN monolayer assembly, a key feature for maintaining the stability of AuNPs. 33 To obtain a stable suspension of lysine-modified AuNPs, we sought a feasible alternative peptide substrate. Poly(L-lysine) (PLL) is a synthetic peptide consisting of a long chain of lysine residues and has been used as a coating layer to obtain particles with excellent colloidal stability.…”